Presentation on theme: "GG3019/GG4027/GG5019 An Introduction to Geographical Information Technology and GIS Geographical Information Systems and Geospatial Data Analysis David."— Presentation transcript:
GG3019/GG4027/GG5019 An Introduction to Geographical Information Technology and GIS Geographical Information Systems and Geospatial Data Analysis David R. Green G12 – 2324
GeoDatabase Data Models What is a geodatabase (data model) ESRIs ArcGIS Geodatabase Data Models Marine Data Model (MDM) Application of the MDM (separate PPT)
Data Models ESRI ArcGIS (successor to ArcView) GeoDatabase The geodatabase provides the common data access and management framework for ArcGIS that enables you to deploy GIS functionality and business logic wherever it is neededin desktops, servers (including the Web), or mobile devices. With this architecture you have the tools to assemble intelligent geographic information systems (ESRI)
Data Models ArcGIS has a well-defined model for working with data This generic model, called the geodatabase (short for geographic database), defines all the types of data that can be used in ArcGISfor example, features, rasters, addresses, and survey measurementsand how they are represented, accessed, stored, managed and processed. The geodatabase is a common framework shared by all ArcGIS products and applications.
(Geo)relational model Geodatabase model
Object-oriented data modeling lets you characterize features more naturally by letting you define your own types of objects, by defining topological, spatial, and general relationships, and by capturing how these objects interact with other objects.
Data Models The goal for the ArcGIS Data Models is to provide a practical template for implementing GIS projects. Common starting point results in the creation of data model design templates that simplify the integration of similar data sets at the local, state/provincial, national, and global levels.
Data Models The geodatabase offers you the ability to: Handle rich data types. Apply sophisticated rules and relationships. Access large volumes of geographic data stored in both files and databases. The geodatabase is more than a manager of geographic data, it also implements sophisticated business logic that, for example, builds relationships between data types, such as topologies and geometric networks; validates data; and controls access.
Data Models The geodatabase supports multiple formats of spatial data including: · Simple features such as shape files · Custom features with business logic and editing rules · Attribute data · Metadata · Images · Raster/Grid data · CAD data
Data Models How does a GIS data model work? An ArcGIS data model is written in a graphical model language (Visio tm ) that provides both a diagram of the data structure as well as UML (Universal Modeling Language) code. UML code can be directly ported to the GIS to create an empty database structure defining all of the necessary relationships and dependencies.
Data Models Data Dictionary UML
Data Models Address Agriculture Archiving Atmospheric Basemap Biodiversity Census Boundaries Defense-Intel Energy Utilities Forestry Geology Health Historic Preservation and Archaeology Homeland Security Hydro Local Government Marine Petroleum Pipeline Telecommunications Transportation Water Utilities
Image courtesy of PISCO, OSU Marine Data Collection
Marine data is collected through a wide range of: Methods Instruments Time scales Periodicity Precision Accuracy
Marine Data Model The marine data model development will provide data managers with a readymade model for marine data so that they can spend more time at sea collecting data and in the lab analyzing their information, and less time at the computer planning the data structure. It should also be useful to GIS practitioners working as academic, government, or military oceanographers, coastal and marine resource managers, consultants, technologists, archaeologists, conservationists, geographers, fisheries managers, scientists, ocean explorers, and mariners alike (ESRI)
What is the MDM? A geodatabase template A new way to spatially model marine data A database used to assemble, store and query data Model that captures the behavior of real-world objects
Basic template for implementing GIS projects –input, formatting, geoprocessing, creating maps, performing analyses Basic framework for writing program code and maintaining applications –development of tools for the community Promote networking and data sharing through established standards Purpose of Marine Data Model
Georelational to Geodatabase Model Coverage (Arc/Info) and shapefile (ArcView) data structures Features are aggregated into homogenous collections of points, lines, and polygons with generic, 1- and 2-dimensional "behavior" Cant distinguish behaviors –Point for a marker buoy, same as point for any observation Smart Features in a geodatabase
Geodatabase Concepts ESRI's new data object-oriented data model –objects, features, behaviors Object –in ArcGIS an object is non-spatial it is NOT a point, line, or area it has no geographic location –it has no shape attribute in its table –ship, vehicle, … customer, lake, house Feature –an object that has geographic location –a point, line, area, TIN, raster
Geodatabase Concepts Geodatabase –Collection of feature data sets, rasters, TINs –All data in relational tables –Behavior is coupled with features through rules –No more division between ARC and INFO (as in ESRIs older GIS ArcInfo)
The common marine data types listed here are evolving and changing with review of the data model. Data Models
The primary ESRI feature classes are the building blocks of the data model. These are the most commonly used features that provide a topological structure for the underlying data.
Steps in Data Model Process Data model template – few weeks to months Mature data model – up to few years Draft Model Review, Projects Final Model
Steps in Data Modeling (1) Model the user's view of data –what are the basic features needed to solve the problem? (2) Select the geographic representation –points, lines, areas, rasters, TINs (3) Define objects and relationships –draw a UML diagram (4) Match to geodatabase elements –specify relationships, behaviors (5) Organize geodatabase structure
Userss View of Data A visual representation of the elements of the data model as they relate to important aspects of marine data collection and analysis.
UML to ArcGIS 8
t/data-models.html odels.matrix Some Marine Data Model Links
Some of the benefits of the geodatabase data model are: A uniform repository of geographic data. All of your geographic data can be stored and centrally managed in one database. Data entry and editing is more accurate. Fewer mistakes are made because most of them can be prevented by intelligent validation behavior. For many users, this alone is a compelling reason to adopt the geodatabase data model. Users work with more intuitive data objects. Properly designed, a geodatabase contains data objects that corresponds to the users model of data. Instead of generic points, lines, and areas, the user works with their objects of interest such as transformers, roads, and lakes. Features have a richer context. With topological associations, spatial representation, and general relationships, you not only define a features qualities, but its context with other features. This lets you specify what happens to features when a related feature is moved, changed, or deleted. This context also lets you locate and inspect a feature that is related to another.
Better maps can be made. You have more control over how features are drawn and you can add intelligent drawing behavior. You can apply sophisticated drawing methods directly in ArcInfos mapping application, ArcMap. Highly specialized drawing methods can be executed through writing software code. Features on a map display are dynamic. When you work with features in ArcInfo, they can respond to changes in neighboring features. You can also associate custom queries or analytic tools with features. Shapes of features are better defined. The geodatabase data model lets you use define the shapes of features using straight lines, circular curves, elliptical curves, and Bezier splines. Sets of features are continuous. By their design, geodatabases can accomodate very large sets of features without tiles or other spatial partitions. Many users can edit geographic data simultaneously. The geodatabase data model supports work flows where many people can edit features in a local area, and then reconcile any differences that emerge.